How CoR Testing Discrimstes

Here's how the comparison of COR between these two types of paddles can be misleading:

1. Different Mass Distribution

   - Conventional hollow cell paddles have a non-uniform mass distribution, with the mass concentrated in the paddle face and the cell walls. This results in variations in the effective mass across the paddle face.

   - Foam-filled cell paddles have a more uniform mass distribution due to the foam injection throughout the core. The foam fills the interior of the cells, providing a consistent effective mass across the paddle face. Increased effective mass at a given impact point will effect return energy.

2. Localized Delamination 

   - In conventional hollow cell paddles, the rebound effect of delamination is more localized and varies depending on where the ball strikes the paddle face. The hollow cells can deform and spring back differently, leading to inconsistencies in the trampoline effect.

   - Foam-filled cell paddles have a more uniform material properties due to the consistent foam distribution. The foam compresses and rebounds evenly across the paddle face, providing a reduced likelihood of local dead or hot spots.

   - The differences can impact the COR, as it affects how much energy is returned to the ball upon impact.

3. Vibration Dampening

   - Conventional hollow cell paddles have less vibration dampening compared to foam-filled cell paddles. The hollow cells allow for more vibrations to propagate through the paddle, which can affect the ball-paddle interaction and the resulting COR. These paddles have higher natural frequencies and lower contact time with the ball.

   - Foam-filled cell paddles have better vibration dampening properties due to the foam injection. The foam absorbs and dissipates vibrations more effectively, providing a more stable and consistent ball-paddle interaction. Better effective mass leads to greater return energy. 

   - The differences in vibration dampening can influence the COR, as it affects how much energy is lost during the impact.

4. Paddle Stiffness and Flex

   - Conventional hollow cell paddles may have variations in stiffness and flex across the paddle face due to the non-uniform distribution of the hollow cells. This can lead to inconsistencies in the COR depending on the impact location. Reduce dampening and higher natural frequency lead to a smaller sweet spot.

   - Foam-filled cell paddles have a more uniform stiffness and flex due to the consistent foam distribution. The foam provides a more even response across the paddle face, resulting in a more consistent COR.

   - The differences in paddle stiffness and flex can affect how the ball compresses and rebounds off the paddle, influencing the COR. This is where a conversation about Ball performance should start.

5. Testing Conditions

   - When measuring the COR, the testing conditions and methodology can greatly influence the results. Factors such as the ball type, impact velocity, impact location, and environmental conditions can all affect the COR values obtained.

   - If the testing conditions are not carefully controlled and standardized, the comparison of COR between conventional hollow cell paddles and foam-filled cell paddles may not be accurate or reliable.

   - Ensuring consistent and fair testing conditions is crucial for making a valid comparison of COR between different types of paddles.

In summary, comparing the COR between conventional hollow cell paddles and foam-filled cell paddles is not a straightforward apples-to-apples comparison. The differences in mass distribution, trampoline effect, vibration dampening, paddle stiffness, and testing conditions can all influence the COR values obtained. It's important to consider these factors and the inherent differences in paddle construction when interpreting and comparing COR values between different types of paddles. A more comprehensive and standardized testing approach is necessary to make fair and accurate comparisons of COR across different paddle technologies.

We are at a point in the sport where we must be extremely careful not to limit material and innovation. PBCoR appears to be said to specifically eliminate non-conventional paddles. The sport is at a point where advanced paddles and conventional paddles behave so differently that we must take account of how both of these models perform. If this rule is misapplied it will not solve the ball velocity problem. As long as players can slap on lead tape that will never be solved and will be unlimited. It's time to stop blaming paddles for behaving the way they do. We should not be surprised that non-conventional paddles are performing far different than conventional paddles. If coefficient of restitution is used to promote conventional designs and eliminate unconventional designs it will be a massive disservice to the sport and players as a whole.